What type of fuel consumption can I expect offroad

[Hammer H]

Hi Guys

heading north soon [bigsmile1]and on one remote 400 km stretch I will need to carry fuel.

Any ideas of fuel consumpition over a mixture of rock and sand tracks i expect the speed to be 20-40 kph

Cheers

Paul

[prelude]

Depends on tyres, load, stuff like that.I usually count +20% over normal driving.

In any case, let me know how much you actually used! I would like some more detailed usage figures myself since I do not have sand driving figures myself for example.

Cheers,
-P

[Hammer H]

Thank you

will let you know the stats in 3 weeks

[loanrangie]

High 20's/L at a guess.

[prelude]

sam eyles got 30L/100 in his much larger V8 back then. I would indeed go for 25L/100 to be safe at least.

-P

[Saulman1010]

I have 23L100 off road rock hopping and hill climb but I once had 26L100 (I was tail end charlie with a box trailer on a childrens bike hike- warning lights and signs, on the run bike repairs and first aid).

[Hammer H]

Ok driving 13ks averaging 9kph in low range across desert, mostly spinifex some rock, dodging and weaving not to get stakes in tyres we were at 61.5/100

https://uploads.tapatalk-cdn.com/20220721/72bf8e7044c5701c3d19be8328ff9dc4.jpghttps://uploads.tapatalk-cdn.com/20220721/fe6fec8694cfe4a3bb72d20693746350.jpghttps://uploads.tapatalk-cdn.com/20220721/632c39b3c945ffb96390542baea60d2b.jpghttps://uploads.tapatalk-cdn.com/20220721/89bd5d59db3168b0778d98155acafb6a.jpg.

I was expecting 30/100

[Hammer H]

Driving on dirt tracks for 28.2 K’s average speed 32 km/h - 22.8/100

https://uploads.tapatalk-cdn.com/20220721/488246bdcc6fa65d99544d3a4fb99b92.jpghttps://uploads.tapatalk-cdn.com/20220721/c9e039b84f0f6971993f163c8f60793d.jpghttps://uploads.tapatalk-cdn.com/20220721/0cab79588172d74d40d16facbee25428.jpghttps://uploads.tapatalk-cdn.com/20220721/0665b3c2c8eeb057233fe3be34271d3d.jpghttps://uploads.tapatalk-cdn.com/20220721/882c2f456fdc8a2ae8a9153f6ae2eefd.jpg

[Hammer H]

And towing trailer on bitumen at 100kph 22/100https://uploads.tapatalk-cdn.com/20220721/577197e9bf2692150336545bed5d3cd1.jpg

[Tombie]

Are you running stock gearing?

[Hammer H]

yes stock gear,

33inch tyres

[Tombie]

yes stock gear,

33inch tyres

That will have contributed to the higher consumption to an extent.

[Hammer H]

About 10%

[prelude]

I would expect the crawling to use up some fuel yes but my word! That's a lot.

In my experience though the trip computer takes a LONG time to settle properly so perhaps it still needed some time I dunno.

In any case, the 33" tyres will definitely have an influence. On paper I have 31.7" tyres and I can already feel the sluggishness and increased consumption. Do not forget however that the computer does not know you have larger tyres than stock. 33" from 29" is 15% larger at least I should think? So you need to take 15% OFF the fuel usage since it is calculated against the trip computers distance counter. (ie. you are using x amount of fuel over y amount of KM's but since your km's are out by 15% you need to substract that to get "real" numbers)

Doing that on your figures you end up with:

52/100 for crawling
19/100 for dirt tracks and around the same for a trailer


Do you have any other modifications to your vehicle? Engine in particular.

Cheers,
-P

[Hammer H]

no other mods, other than electric Thermo fan.

True I should calculate closer to 15%

I think the towing trailer and track l/100 is ok.

Just the off road high. I also left the tyres at 38 and 36 psi to avoid stakes, which seemed to work as no flats, although I still need to pull a few out of the tyres. Others on a similar trip have seen 4 flats.

[prelude]

Did you drive on dirt tracks in low or high range?

Cheers,
-P

[Hammer H]

The 60/100 was off the tracks across the desert and spinifex making new tracks. Low range.

[prelude]

I take it this was a test ;) I hope the total average consumption will be manageable on the eventual big trip. Making new tracks is slow going but once you can get over almost idle speeds, even in low range, the fuel consumption should go down a bit? I hope?

Did you ever get out of first or second low during that part?

Cheers,
-P

[Tombie]

About 10%

If you’re basing that on gearing variation alone it will be significantly off.

When I went down the rabbit hole of building up my D1 V8 gearing wasn’t the only impact.

Inertial mass, resistance and gearing all played a big part.
From memory it was closer to 20-25% increase in fuel burn.

Redoing the gearing improved it a bit, but it never got back to anywhere near stock. Always about 12-15% worse than stock.